The tenderizing of meat and the destruction of micro-organisms on and in meat can be accompanied by generating a shock wave in a non-compressible fluid and allowing the shock wave to pass through meat, which is preferably sealed in a plastic bag for cleanliness and ease of handling.
The tenderizing effect can be roughly doubled by placing the meat adjacent a reflective surface in the water, such as heavy steel plate, which reflects the wave back through the meat. Thus, the shock wave front passes through the meat, reflects from such surface, and passes a second time through the meat, crossing a portion of the still incoming wave. The maximum effect occurs in the region of the supported meat where the reflected wave crosses the incoming wave.
For uniform shock intensity, the inside of a heavy steel hemispherical tank can be lined with meat packages and the inside of the tank filled with water. An explosive chemical charge is placed at the center point and detonated, or an electric spark is discharged to generate the shock wave which travels outward through the water, tenderizing all the meat relatively evenly.
Tenderizing meat in this manner has many advantages, including instant tenderization, low cost, and saving of energy, as well as killing of bacteria. There are no unsavory or known unhealthy results to the meat.
Explosive meat tenderizing is discussed in Long U.S. Pat. Nos. 5,328,403 and 5,273,766, both of which are entirely incorporated herein by reference. An improved water deflector is shown in Long et al U.S. Pat. No. 5,841,056 also incorporated by reference, and corresponding WO 97/456697. The process disclosed in these patents is known as the Hydrodyne Process. In the exemplary embodiments disclosed by these patents, the shock wave is produced by the detonation of a high explosive. It will be understood that large forces are generated by the explosions, which must be energetic enough to create a powerful shock wave and therefore are energetic enough to destroy common materials and break containment devices which are not strong enough.
The main containment device is a large stainless steel vessel or tank which includes a shock-reflective wall, several inches thick, of generally hemispherical shape. The generally hemispherical portion is preferably extended by a circular-cylindrical collar joining the hemisphere along its upper edge (a great circle) and extending upwardly. The collar provides a well for water above the central detonation point, the latter of which is at the upper edge of the hemispherical portion and the lower edge of the circular-cylindrical portion. The water above the detonation is necessary to contain the initial force of the explosion. Preferably the depth of the detonation point below the water surface in the filled tank is greater than the spherical radius of the hemisphere.
When an explosion occurs at the center of the tank, a shock wave travels outward in all directions initially at about 16,000 to 20,000 feet per second, which is well above the speed of sound and shock waves in water. When it impinges on the tank wall, the steel from which the wall is formed elastically stretches to a small degree due to the great amount of force. About 20% of all the explosion energy in the shock wave goes into hoop expansion. Typically 30% to 50% of all the explosion energy goes into the shock wave, so the total energy in hoop expansion is considerable. The force on the tank wall due to the shock wave is rapidly applied, rising to a peak in about 10 .mu.s (10 microseconds). The shock pulse lasts for about 30 to 60 .mu.s. The lower half of shock pulse wave front will partially rebound from the tank wall and partially pass through; the upper half will likewise partially rebound from the cylindrical portion of the tank steel wall and also from the air/water surface above. Echoes will bounce back and forth for some time.
After the shock wave pulse, a slower pulse pushes on the tank wall. The slower pulse is due to a reaction force caused by the upward surge of water which is pushed out of the tank by the expanding bubble of gas (steam in the case of an electrical-discharge explosion). This pulse lasts for about a period of as little as 0.2 to 0.4 ms (milliseconds), up to about 1 ms or even more. The peak downward reaction force caused by a typical chemical explosive charge of 0.3 kg (2/3 lb.) of TNT is at least 200,000 kg (440,000 pounds).